When you’re 100% certain that you want to resign from your current job, one of the first things to do is have a look at your contract and assess whether there is a certain amount of notice you need to give your boss.
If there isn’t, the polite thing to do is give 2 weeks notice, but if you really want to go down in the good books, it’s probably better to give as much notice as possible. You should also make sure you resign in person, and have a resignation letter handy because it may be required of you.